n00b question - what is this (brake system)

marty085 · Postby **marty085** » Wed Nov 21, 2012 7:40 pm

My genuine apologies for the completely n00b question, but I'm trying to work out what function this has...

It is not mentioned or depicted in the Enthusiast's Workshop Manual, but the Renovation Manual shows an Eezi Bleed connected to it and refers to it as the master cylinder reservoir.

Brake fluid in the "other" master cylinder is nice and clear, but it looks like the fluid in this one is black but then again I'm not sure if the container is playing tricks on my eyes. Can't open it to see as it's semi sealed when you take the lid off.

koop21 · Postby **koop21** » Wed Nov 21, 2012 7:50 pm

That is the clutch reserve which connects to the clutch master cylinder which connects to your clutch pedal

Typically when the fluid goes black your seals are gone and your might find a tiny leak near your clutch pedal, best to check it out.

marty085 · Postby **marty085** » Wed Nov 21, 2012 8:00 pm

Awesome (except for the leak part) thanks mate. Fluid level in it seems to be okay but i'll check it out.

marty085 · Postby **marty085** » Wed Nov 21, 2012 8:02 pm

But hang on, why the heck does the MX5 Renovation Manual show an eezi bleed system connected to it under the Brake fluid renewal section!?

hks_kansei · Postby **hks_kansei** » Thu Nov 22, 2012 9:01 am

marty085 wrote:But hang on, why the heck does the MX5 Renovation Manual show an eezi bleed system connected to it under the Brake fluid renewal section!?

The clutch uses brake fluid. On many cars the brake and clutch share a reservoir, but in the MX5 they're separate.

The manual is probably assuming that since you've got the brake fluid out you'll probably flush and change the fluid for the clutch too.

project.r.racing · Postby **project.r.racing** » Thu Nov 22, 2012 9:14 am

the different colour could just be because of different fluids used. being seperate systems, they could've been changed at different intervals with different fluids.

if you are worried about it. by a $8 500ml bottle of brake fluid and flush it. you'll probably have 350ml left over once done. lol

93_Clubman · Postby **93_Clubman** » Thu Nov 22, 2012 10:08 am

Or clutch fluid simply hasn't been changed for a few years.

hks_kansei · Postby **hks_kansei** » Thu Nov 22, 2012 10:17 am

93_Clubman wrote:Or clutch fluid simply hasn't been changed ever

Changed to the most likely.

marty085 · Postby **marty085** » Thu Nov 22, 2012 10:54 am

Yeah you're probably right.. :shock:

Okay, got all tomorrow arvo off work so this is what I'll be hitting up. Have ordered in a clutch slave cylinder repair kit from Mazda for $30, last time I was under there I noticed it was oozing a bit so may as well hit that up for relatively cheap. Will arrive tomoz.

My clutch lines are gonna bleeeed like they've never bled before.

Thanks heaps to all you guys for the help. This is how I learn, with helpful and cheerful advice

marty085 · Postby **marty085** » Thu Nov 22, 2012 10:59 am

I also read on the net (i think miata.net forums) that the clutch fluid system is vented (i.e. not sealed) so the colour can change due to that... that surprised me actually, is that a load of crap?

93_Clubman · Postby **93_Clubman** » Fri Nov 23, 2012 10:37 am

Yeah, it's vented in the sense that (on the NA8 at least) there's a pin hole in the black plastic screw on/off top of the clutch master cylinder reservoir. Brake fluid is hydroscopic (absorbs moisture) which redues its effectiveness & boiling point over time. Of course boiling point isn't an issue with the brake fluid used in the clutch hydraulic system, but it can be for the brake system, hence recommendation on road cars to change brake fluid every two years, like coolant, & include a clutch fluid change in that regime.